[Webkit-unassigned] [Bug 188598] [JSC] Remove gcc warnings on mips and armv7

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=188598

Mark Lam <mark.lam at apple.com> changed:

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--- Comment #27 from Mark Lam <mark.lam at apple.com> ---
Comment on attachment 351282
  --> https://bugs.webkit.org/attachment.cgi?id=351282
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=351282&action=review

r=me.  The patch looks correct though I think it would be better if we use static_casts in instead of bitwise_casts.

> Source/JavaScriptCore/runtime/ScriptExecutable.cpp:349
> -        return throwException(&state, throwScope, createError(&state, "Forced Failure"_s));
> +        return std::optional<Exception *>(bitwise_cast<Exception*>(throwException(&state, throwScope, createError(&state, "Forced Failure"_s))));

I actually disagree with using bitwise_cast here because we're casting from a pointer to a pointer.  Hence, they are guaranteed to be of the same bit length.  In fact, I think a static cast would be more meaningful because it enforces that there's a "is a" relationship between the source (JSObject*) and the result (Exception*).  The times when we should use bitwise_cast are when casting between the bit value of non-pointer types (e.g. integers) and pointers.

Are you sure that this is where Yusuke is asking to apply the bitwise_cast?

> Source/JavaScriptCore/runtime/ScriptExecutable.cpp:357
> +        return std::optional<Exception *>(bitwise_cast<Exception*>(exception));

Ditto.

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